Icons not loading on my computer

Okay, I have a very strange problem. I'm currently using Windows XP and sometimes when I'm on the desktop and want to click/open any icon - whether it's Firefox, a .txt file or whatever, the file/program won't load unless I continually hit ctrl, alt, delete. This doesn't happen all the time, but it's fairly frequent.

Also, sometimes I'll leave the desktop alone (or have a webpage open) for no longer than 10 min. and the only thing that's showing when I get back is the wallpaper with no startup menu, no desktop items, or anything. I have to restart my computer by holding the button on the computer to fix this problem. It's very tiresome to have these problems, espcially since the computer is less than 6 months old...